Evidence of sex reversal in the gonads of chicken embryos after oestrogen treatment as detected by expression of lutropin receptor

Abstract

In chicken embryos, there is a difference between the sexes in the onset of lutropin receptor mRNA expression in the gonads. The effects of oestrogen on lutropin receptor expression were studied to investigate the mechanism controlling this difference. Lutropin receptor mRNA expression was detected in the ovaries of sesame oil-treated control female embryos on day 12 of incubation, while no expression was found in the testes of the male controls. Oestradiol administration to genetically male embryos before sexual differentiation resulted in gonadal sex reversal which was characterized histologically by the proliferation of cortical cords and the presence of lacunae. Lutropin receptor expression was detected in the feminizing testis on day 12 of incubation. Administration of aromatase inhibitor (CGS 16949 A) to genetically female embryos before sexual differentiation inhibited the formation of cortical cords, although a relatively weak expression of lutropin receptor was detected. These results indicate that early expression of the lutropin receptor is regulated by oestrogen.

Investigation of Sex Reversal in Layer Chickens in Bangladesh

“…Individual response and exposure of concentration of chemicals may have effects on lower percentage of sex reversed birds over the populations (Crews et al, 2000). Estrogen has long been considered a factor in the determination of gonadal sex in some non-mammalian species (Akazome and Mori, 1999). Average estrogen concentration (5pg/ml) in case chickens was subnormal and similar to level of estrogen (6-7.3 pg/ml) in adult male chicken (Schrocksnadel et al, 1973).…”

Manipulation of Estrogen Synthesis Alters MIR202* Expression in Embryonic Chicken Gonads1

“…Changes in gonadal morphology and the expression of known testis-and ovary-associated genes are known to occur following estrogen modulation of gonadal differentiation [6,[12][13][14][15]32]. The reduction of MIR202* expression in estrogentreated versus control male E9.5 gonads correlated with morphological and histological changes characteristic of ovarian differentiation, namely, an increase in gonadal asymmetry and the development of an ovarian-like cortex containing relocalized PGCs in the left gonad (Fig.…”

“…Inhibiting the activity of aromatase is sufficient to cause female-to-male gonadal sex reversal [6,7,12,13]. Conversely, treatment of male embryos with exogenous estrogen prior to the onset of gonadal differentiation is able to feminize development of the male left gonad, resulting ovary, or ovo-testis formation [8,14,15].…”

The pathway to femaleness: current knowledge on embryonic development of the ovary

“…In these species, estrogen is the ovary-determining factor. Estrogen treatment of male embryos during the critical period of development in fish (Guiguen et al, 1999;Kobayashi et al, 2003), frogs (Mackenzie et al, 2003;Kato et al, 2004), reptiles (Pieau and Dorizzi, 2004), chicks (Abinawanto et al, 1996;Mittwoch, 1998;Akazome and Mori, 1999), or in marsupial newborns (Shaw et al, 1988;Baker et al, 1993;Fadem, 2000;Coveney et al, 2001;Renfree et al, 2001) can cause testis-to-ovary sex reversal. In addition, inhibition of estrogen synthesis in female embryos leads to testis development in these species.…”